What are the main hazards of debris flow?

Lead: Debris flow is a unique disastrous geological phenomenon in mountainous areas. When you find it, you should climb to a high hillside immediately. Climb as high as possible. The faster you run, the better. So, do you know what the main harm of debris flow is? What are the hazards of debris flow?

Main hazards of debris flow

(1) Hazard to residential areas: One of the most common hazards of debris flow is rushing into villages and towns, destroying houses, factories, enterprises and institutions and other places and facilities. Flooding people and animals, destroying land, and even causing disasters such as village destruction and death.

(2) Harm to highways and railways: Debris flow can directly bury stations, railways and highways, destroy subgrade, bridges and culverts and other facilities, cause traffic interruption, and also cause subversion of running trains and cars, resulting in serious personal injury and death accidents. Sometimes, debris flows into rivers, causing great changes in rivers, indirectly destroying roads, railways and other structures, and even forcing roads to change lanes, causing huge economic losses.

(3) Harm to water conservancy and hydropower projects: mainly destroying hydropower stations, water diversion channels and ditch-crossing buildings, silting up and burying the tailrace of hydropower stations, silting up reservoirs and abrading dam surfaces.

(4) Harm to the mine: mainly destroying the mine and its facilities, silting up the mine roadway, hurting the mine personnel, causing the mine to stop production or even scrap.

Remind you: listen to local weather forecast and early warning information in time; When carrying out outdoor activities in mountainous areas, we should choose the flat highland as the camping site, and try our best to avoid the curved concave bank or narrow and low convex bank of rivers (ditches); Never build a camping tent in a ditch or a low-lying place in a ditch. In case of long-term rainfall or rainstorm, be alert to the occurrence of mudslides; When there are signs of debris flow, you should immediately observe the terrain and run to the slopes or highlands on both sides of the valley. Don't hide under steep slopes with rolling stones and a lot of deposits, and don't stay in low-lying places.

Distribution of Debris Flow and Debris Flow in China

1, debris flow distribution

Debris flow disasters all over the world, especially in China, Japanese, Russian, European Alps, Pacific Rim mountainous areas, etc. According to statistics, there are more than 60,000 mudslides in Russia, 9,000 in Czech Republic, 6,300 in Japan, 4,200 in Austria and 60,000 in China.

2. Debris flow in China

Debris flow is a natural phenomenon, which occurs in mountain streams and valleys and often rains heavily. Therefore, most historical records are attributed to floods. Since 1950s, people have made field observation, dynamic monitoring and systematic research on debris flow, which has made the actual research on debris flow clear and gradually developed into a new discipline. The study of debris flow also began in this period. Although it started late, it has entered the world advanced level.

China has a vast territory, complicated geological and geographical conditions and widespread debris flow. Glacier debris flow is a high mountain glacier debris flow in the west and a low mountain and hill in the east. There are 77 1 counties and cities in China, and most of them are in some mountainous areas of Yunnan, Sichuan, Gansu, Tibet, Shaanxi, Qinghai, Xinjiang, Hebei, Beijing, Liaoning and Jiangxi provinces and cities.

3. Knowledge about debris flow

In order to distinguish between flood and debris flow, three quantitative indexes are given: first, the volume of sediment and debris exceeds 30% during flood; Second, the hydraulic power exceeds 0/.4 tons per cubic meter/kloc; Third, the sand content per cubic meter exceeds 600 kilograms. As long as the quantitative indicators reach or exceed these three indicators, it can be defined as debris flow. On the other hand, if any of the three indicators is lower than this, it can't be a mudslide, so it's called a flood.

The formation of debris flow must meet three basic conditions: first, steep terrain, second, abundant water, and third, abundant loose deposits. The mechanism is that the steep riverbed is saturated by heavy rain, and then water flow forms on its surface, which makes the sediments lose their mechanical stability and start to slide, forming debris flow. In addition, the collapsed clods destroyed the structure during the movement, and the water supply may form debris flow.

The development process of debris flow is related to the changes of climate and environment, such as melting glaciers, filling valleys with ice, forming lakes and intensifying gravity erosion on hillsides. This is related to the time occupied by monsoon in a certain area and the prosperity of vegetation in a certain area. According to historical records, during the Three Kingdoms period, the valley in the middle and lower reaches of Baishui River in China was lush with trees and the Baishui River was crystal clear. There is no record of debris flow, which belongs to the debris flow-prone area. The middle and lower reaches of Baishui River are flanked by rippling riverbeds. It is also related to the active intensity of regional geological structures, topography, rock hardness and other factors.